Press for extruding seamless tubes from unbored billets of metals and alloys



PRESS FOR EXTRUDING SEAMLESS TUBES FROM UNBORED BILLETS 0F METALS AND ALLOYS Original Filed Jan, 9, 1926 2 Sheets-Sheet 1 g- 19, A. LIEBERGELD ET AL 1,773,464

lllllllllllll Whey 1930- A. LIEBERGELD ET AL 1,773,464

PRESS FOR EXTRUDING SEAMLESS TUBES FROM UNBORED BILLETS 0F METALS AND ALLOYS Original Filed Jan. 9, 1925 2 Sheets-Sheet 2 VI I by M a or/zey Patented Aug. 19, 1930 Original application UNITED STATES PATENT OFFICE.

ALFRED LIEIBIEJRGIZILDv 0F LA'UFAMHOLZ, NEAR NUREMBE'RG. AND FRITZ SINGER, OF NUREMBERG GERMANY; SAID LIEBERGELD ASSIGNOR T0 FRITZ SINGER, OF

NUREMBERG, GERMANY PRESS FOR EXTRUDING SEAMLESS TUBES FROM UNBORED BILLETS 0F METALS i ALLOYS v This invention relates to an improved method of and an improved press for the hot extruding of seamless tubes from unbored metal billets.

The present application is a division from Serial No. 80,338 filed January 9th, 1926.

Hitherto in extruding tubes according to Dicks process cylindrical billets have been used, said billets being prepared bycomplete or part boring on a drllling machine. The use of unbored billets has the disadvantage that the tubes obtained are of irregular thickness owing to insufiicient means for accurately guiding the piercing tool.

It is true, extruding devices have been known long ago which permit to use also unbored billets. Such known devices consist in the mandrel not being rigidly connected with the punch, but being moved independently of the latter by separate driving means.

But such arrangement includes the drawback that separate devices are necessary to' control the mandrel piston independently of the punch piston. So not only the contrivances, but also the working method will be complicated considerably, in consequence of which practice preferred to use single working presses and to take. into the bargain the.

boring of the billets.

The objectof our invention is to providemeans which permit a relative movement of the mandrel towards and away from the punch and dispense with separate means for driving and controlling the mandrel.

For this purpose the mandrel will be mounted on the main reciprocating member moved by the driving means of the press, whilst the hollow punch guiding the mandrel will be secured to a subsidiary reciprocating member. This subsidiary reclprocating member is arranged on the main reciprocating member in such a manner that it may be slid Within certain limits in the same lifting axis as the main reciprocating member towards and away therefrom. Means are provided to hold both reciprocating members in their most remote relative position during a part of the stroke so that the punch will touch the billet before the mandrel enters the billet, to exert by the intermediary of the punch back stroke.

filed January 9,1926, Serial No. 80,338, and in Germany January 12, 1925: Divided and this application filed August 2, 1929. Serial No. 383,015.

vided to couple together said reciprocating members in a specific position and to return them lnto their initial positionduring the By arranging a subsidiary reciprocating member, whlch is moved partly dependently, partly independently ofthe movement of the mam reciprocating member, but automatically controlled by this movement, the pressing device, according to the invention, permits to execute the steps of fixing the raw billet within the container, the perfectly centrically plercing and extruding of the billet in one single continual operation at the forward stroke of the press.

A press embodying the invention is show in the accompanying drawings.

Referring to' said drawings Figs. 1-5 are front elevations of the press being partly in vertical section and showing diflerent stages of the extrusion operat1on.

Referring to Fig. 1, the cylindrical billet a, heated to the necessary temperature, is inserted into the bore'of the container 6, the bottom of which is provided with a matrix die 0. This container 6 is fixed on the table 03 of the uprights e of the press, which is shown as a vertical frame, but which might also be arranged horizontally or at any other suitable angle.

The crank mechanism of the press, for which an eccentric mechanism might be substituted, comprises a crank shaft f, a crank g, a connector h, a connecting rod 2', a ball and socket joint 70, which may be constructed as a pivot joint and a reciprocating guide-piston Z for guiding the connecting rod. A perforating mandrel m is fixed in the bottom of the piston Z and its diameter corresponds to the inner diameter of the tube to be extruded.

The punch 12, which is hollow and concentrically surrounds the perforating mandrel m, is fixed in the end face of a freely movable plunging piston 0, the inner surface of which serves to guide the piston Z, said plunging piston being guided in the uprights e on its outer surface. The guiding piston Z with the mandrel m is positively moved from the ment of the material to be perforated serve as driving means. The mechanical driving means consists of a cam disk p keyed on the crank shaft and having a contact face 1) which acts upon a roller 9 mounted in a trans verse 'bridge 1v The bridge is fixed in the open end of the plunging piston 0v so that saidroller can be easily rotated. Instead of the cam disk mechanism described a toggle lever mechanism or a controlling grooved disk gear can be used.

The press operates as follows: Fig. 1 shows the position of the driving mechanism, the pistons and the rams prior to the starting of the press in the upper dead center position. The piston 0 is suspended by its bridge r on the piston Z and descends with the same. After the punch nhas come in contact with the billeta the piston I alone continues the descend. The contact-face 7) of the cam disk p comes into contact with the roller q and lowers the same and the piston 0 with the punch at slow speed until the billet has completely filled the gap between the punch and the die 0. r

The preliminary pressing of the billet a is completed at the moment at which the cam disk 1) moves away *from the roller q. The punch n rests fora moment on the preliminarily pressed billet a without exerting any movement and without exerting any further pressure than that of its own weight and that of the plunging piston 0.

As shown in Fig. 3 the mandrel m which continues its descending movement now per-' forates the billet. The material displaced by this step makes the billet a longer whereby the punch n together with the plunging piston 0 are pushed slightly upward. Only a small portion of the material displaced by the mandrel m drops as a slug 8 through the bore 25 of the working table d which is designed to receive the finished tube to.

As shown in Fig. 4 the guide piston Z, continuing to descend, directly contacts. after the piercing hasbeen completed with the bottom plate of the plunging piston 0, so that the two pistons Z and 0 and the two punches m and n will, from this moment, descend together and press out the material of the billet I 1 in the shape of a tube it through the ringshaped opening 0 (Fig. 4 which is formed between the stationary 'die 0 and the descending mandrel m. At the end of the stroke the preliminary treatment of the billet a and the At the return stroke crank mechanism f, g,

h, 2', 70, 1 will the mandrel m move back according to Fig. 5 until the guide piston Z which guides the connecting rod comes into contact with the bridge 7' which carries the roller, so that from this nfoment the plunging piston 0 with the punch n is drawn along and returns into the initial position to which the cam disk p has also returned. In Fig. 5 the elements are almost in the initial position in which they are shown in Fig. l.

The tube M which is still connected with the residue w from extruding is then severed in a manner known per se, whereupon the tube and the residue from extrudlng can be removed.

Instead of the guide piston and the plunging piston engaging the one with the other, pistons may be used for the punch and the mandrel which move side by side.

1. A press for extruding seamless tubes from unbored billets of metals and alloys, comprising a main reciprocating member, a perforating mandrel secured on said memher and guided in a hollow punch, said punch being secured on a subsidiary reciprocating member which is guided in the press frame and mounted on the main reciprocating member adapted to be slid Within certain limits in the same lifting axis as the main reciprocating member towards and away therefrom, means to Hold both reciprocating members in their most remote relative position during a part of the stroke to effect a pressure on the billet bv the punch when the latter touches the billet and to permit the punch to be pushed back by the rising material while the billet is being pierced, means to couple together said reciprocating members in a specific position, so that both members finish together the remainder of the working stroke, and means to return both reciprocating members into their initial position. during the back stroke.

2. An upright press for extruding seamless tubes from unbored billets of metals and alloys comprising a main reciprocating member, a piercing mandrelsecured on said member and guided in a hollow punch, said punch being secured on a subsidiary reciproeating member guided in the press frame and suspended on the main reciprocating mem her. said subsidiary reciprocating member being adapted to be slid within certain limits in the same lifting axis as the main reciprocating member towards and away there- -.rom to press on the billet by it-s'own weight and by the weight of the punch and to be pushed back by the rising material while the billet is being pierced, means to couple to- 1 g'ether said reciprocating members in a specific position, so that both members finish driven by mechanical means, a piercing mandrel secured on said member and guided in a hollow punch, said punch being secured on a subsidiary reciprocating member, guided in the press frame and mounted on the main reciprocating member, said subsidiary reciprocating member being adapted to be slid within certain limits in the same lifting axis as the main reciprocating member, towards and away therefrom, cams for operating said subsidiary reciprocating member by means of rollers, said cams being driven by the same driving shaft as the main reciprocating member and including a movement adapted to drive the subsidiary reciprocating member,

before the mandrel contactswith the billet, until it presses thereon, and to allow the punch to be pushed back while the billet is being pierced, means to couple together said reciprocating members in a specific position,

so that both members finish together the rest of the working stroke, and means during the back stroke to return both reciprocating members into their initial position.

4. A press for extruding seamless tubes from unbored billets of metals. and alloys,

comprising a main reciprocating member shaped as a piston, mechanical means for operating said piston, a shank embodying a mandrel portion secured on said piston and guided in ahollow punch, said punch secured on a subsidiary reciprocating mem ber shaped as a closed end cvlinder and guided in the press frame, said cylinder surrounding and guiding the first named piston and adapted to he slid within certain limits towards and away from the quoted piston, cams for operating the cylinder by means -of rollers, said cams driven by the same driving shaft as the piston and including a movement adapted to drive the subsidiary reciprocating member. before the mandrel touches the billet, until the punch presses the billet, and to allow the punch to be pushed on a subsidiary reciprocating member shaped as a closed end cylinder and guided in the press frame, said cylinder surrounding and guiding the first named piston and adapfed to press on the billet by its own weight y the intermediary of the punch and to be pushed back by therising. material while the billet is being pierced, a bottom in the c linder by which the piston and the cylin er are coupled when the piston contacts with said bottom, and a carrier mounted on the cylinder, adapted to carry back the cylinder into its initial position when the piston'returns to its initialposition.

In testimony whereof we afiix our signaback while the billet is being pierced, a bottom in the cylinder by which the piston and I the cylinder are coupled when the piston contacts with said bottom, and a carrier mounted on the cylinder, adapted to carry back the cylinder into its initial position, when the piston returns to its initial position) 5. An u right press for extruding seamless tubes from unbored billets of metals and alloys, comprising a main reciprocating member shaped as a piston, a crank gear for operating said piston, a' shank embodying V a mandrel portion secured on said piston and guided in a hollow punch, said punch secured 

